How do river basin characteristics influence flood wave propagation?

该项目旨在更好地了解高原流域形态和地貌对洪水特征的影响。数十亿人居住在河流附近，遭受洪水的负面影响。由于气候变化改变了全球河流洪水的规模和频率，它们面临的风险正在增加。流域地貌通过改变流域的水文和沉积连通性来过滤景观对降雨的响应。先前的研究表明，河道内形态的变化会影响洪水风险；这项工作将超越河道，着眼于山坡和河流的交界面。流域演变和结构如何影响洪水的量化将使流域地貌与其他因素（如土地覆盖、人为干扰和气候变化）对洪水动力学的影响脱钩。这项工作将把高地流域过程与下游洪泛平原联系起来，以预测先前的景观条件将如何改变随后的洪水事件。该项目的目标将通过一系列的三篇论文来实现。第一篇论文将着眼于英国、北美或喜马拉雅山的高地地区，通过比较盆地来观察过去和现在的盆地地貌如何影响洪水的产生。区域选择取决于所需的地貌动力学水平和河坡耦合的清晰度。利用卫星图像（取决于所选地区）、数字高程模型（可能来自卫星摄影测量）和旧地图对盆地形态测量学和地貌变化率进行量化。下游测量站将有助于阐明流域地貌对由广义极值分布产生的各种洪水复发间隔的影响。将比较具有类似降雨机制（从降雨雷达数据中提取）、土地覆盖和季节性的集水区，以消除这些对洪水产生的影响。在第二篇论文中，将使用一个模型（例如Hydro-JULES）研究已确定的流域形态对洪水特征的影响。通过使用第一篇论文中的“完美景观”和自然景观，蒙特卡罗模拟将阐明集水区的地貌变化轨迹如何影响下游的洪水。将对景观变化的影响进行量化，根据洪峰持续时间、震级和滞后时间，景观变化如何改变未来的洪水风险。最后一篇论文将通过将发现的概念应用于其他地区，将第一篇论文中探讨的主题联系起来。如果在这个阶段有可能，就可以进行全球高地流域地貌对洪水风险的分析。这可能与气候变化对景观演变的影响联系起来，以便更好地预测景观发展如何改变洪水灾害。如果某些方面无法实现或外部因素发生变化，三纸框架允许项目适应性。它还允许逐步增加工作产出和知识深度，为发展所需的进一步技能和方法提供机会。该项目为国际上的大学、商业利益相关者和政策制定者提供了充分的合作机会。从该项目中获得的知识适用于从自然洪水管理到Hydro-JULES的创建等工作。这将为将流域地貌特征与其他影响洪水变化信号的因素分离开来提供依据。更好地预测河流流域形态如何影响洪水季节，将有助于更好地防范全球洪水风险。

This project aims to better understand how upland river basin morphometry and geomorphology influences flood characteristics. Billions of people live close to rivers and experience the negative effects of flooding.Their risk exposure is increasing due to climate change altering the magnitude and frequency of fluvial flooding globally.River catchment geomorphology filters a landscape's response to rainfall by shifting hydrological and sedimentological connectivity in the basin.Previous work has shown in-channel morphological changes can affect flood risk; this work will look beyond the channel and at the hillslope-river interface.Quantification of how catchment evolution and structure impacts flooding will allow disentanglement of basin geomorphology from other factors such as land cover, human disturbance and climate change on flood dynamics.This work will link upland river basin processes to downstream floodplains to forecast how antecedent landscape conditions will alter subsequent flood events.The project's goal will be achieved by a series of three papers.The first paper will look at an upland region, either in the UK,North America or the Himalayas,to observe howpast and present basin geomorphology impacts flood generation by comparing basins.Region choice depends on the level of geomorphic dynamics required and the clarity of river-hillslope coupling. Basin morphometrics and geomorphic change rates are quantified using satellite imagery (dependent on region chosen), digital elevation models(potentially from satellite photogrammetry)and old maps. Downstream gauging stations will help elucidate basin geomorphometry influence on various flood recurrence intervals generated from a Generalized Extreme Value distribution. Catchments with similar rainfall generation mechanisms (extracted from rainfall radar data), land cover and seasonality will be compared to remove those impacts on flood generation.In the second paper, identified basin morphological impacts on flood characteristics will be investigated using a model (e.g. Hydro-JULES). By using 'perfect landscapes' and natural ones seen in the first paper,Monte Carlo simulations will elucidate howgeomorphological change trajectories in catchments may influence flooding downstream.Landscape change influence will be quantified on how it could change future flood risk regarding flood peak duration,magnitude and lag time.The final paper will link themes explored in the first papers by applying found concepts to other regions.If it was possible at this stage,a global analysis of upland river basin geomorphology on flood risk could be undertaken.This could link with climate change influence on landscape evolution to allow better prediction of how landscape development could alter flood hazards.The three-paper framework allows for project adaptability if aspects become unachievable or external factors change. It also allows for a gradual increase in the work output and knowledge depth, providing chances to develop further skills and methods required. The project offers ample opportunities to collaborate with universities, business stakeholders and policymakers internationally. Knowledge garnered in this project is applicable to work ranging from Natural Flood Management to the creation of Hydro-JULES. It would provide a basis for separating basin geomorphometry from other factors influencing flood-change signals through time. Better prediction of how river catchment morphology influences flood seasons will allow for better preparedness of global flood risk.